Winter feed crops have come under the regulatory spotlight as a source of nutrient and soil loss, but catch-crops look set to become an important tool to help farmers mop-up nutrients left in the wake of intensive grazing and use them to drive drymatter yields.
Catch-crops are sown as soon as possible after a winter feed crop has been grazed.
Josh Brown, Hurunui District Landcare Group coordinator, says catch-crops have been on the regulatory radar and they are likely to be recommended by the Regional Council as part of Good Management Practice – although he points out that they are not going to suit every farm system.
He feels it is unlikely catch-crops will be prescribed, but they are a tool that farmers can use to reduce their nutrient losses.
“They won’t work for everyone, but they are very effective at mopping up excess nutrients.”
Luisetti Seeds has been co-funding a Ministry of Primary Industries Sustainable Farming Fund (SFF) project- which is looking at using catch crops to mitigate nitrate (N) leaching during winter forage grazing.
It has shown that the inclusion of a catch-crop such as Intimidator oats can generate a gross profit of $1800/ha (DM valued at 20c/kg).
That was from a 12 tonne dry matter (DM) per hectare Intimidator oat crop sown into a grazed kale paddock in mid-July and harvested on November 20.
In this particular example-– the oats pulled up 223kg N/ha- N that would have potentially been lost to the environment.
Peter Carey, a field research scientist with Lincoln Agritech, who is carrying out the three-year SFF project, says oats are ideal because they are more winter active, and therefore are growing when the soil microbes start turning the ammonium from the deposited urine into nitrate.
The whole process is temperature related.
“Once the soil temperatures warm up enough to start the oats growing, it is exactly the same time as the nitrification process kicks into gear.”
Oats, with their larger seed, are well suited for drilling in low soil temperatures. They are also robust and have deep roots to capture the soil N.
Farmers wanting to grow an Intimidator Oats catch-crop this year are being encouraged to order their seed now and talk to their Luisetti Seeds agronomist about establishing and growing these highly- productive greenfeed oats.